GRBL0.8版本中有个doc文件夹，下面是关于GRBL大致的框架介绍

1.commands.txt介绍GRBL命令

2.pinmapping.txt介绍GRBL引脚映射

3.resources.txt介绍GRBL用到资源

4.structure.txt介绍GRBL框架

4.1英文如下

The general structure of Grbl
=============================
4.1.1The main processing stack:

1.'protocol'        : Accepts command lines from the serial port and passes them to 'gcode' for execution.
                    Provides status responses for each command. Also manages run-time commands set by
                    the serial interrupt.

                    接收串口命令传递给gcode执行，给命令提供应答，通过串口中断管理程序命令
                  
2.'gcode'           : Recieves gcode from 'protocol', parses it according to the current state
                    of the parser and issues commands via '..._control' modules
                    从1接收G代码，解析G代码
3.'spindle_control' : Commands for controlling the spindle.
                               主轴控制，雕刻机的主轴带刀的轴，与XYZ无关，M3,4,5有关于主轴正反转停止命令
4.'motion_control'  : Accepts motion commands from 'gcode' and passes them to the 'planner'. This module
                    represents the public interface of the planner/stepper duo.
                      从2接收运动命令将其传递给5，相当于一个发出命令的高层接口

5.'planner'         : Receives linear motion commands from 'motion_control' and adds them to the plan of 
                    prepared motions. It takes care of continuously optimizing the acceleration profile
                    as motions are added.
                    从4接收线性运动的命令，并将其添加到准备运动计划中(计算的数据写入唤醒缓冲区)

                    随着运动不断被添加负责优化计算加速度分布图

6.'stepper'         : Executes the motions by stepping the steppers according to the plan.
                          执行动作，用两个定时器来控制三个轴完成相应的动作

4.1.2Supporting files:

'config.h'        : Compile time user settings
                        一些全局变量的宏定义，例如MINIMUM_STEPS_PER_MINUTE最低每分钟跳动多少下，也就是最低

                        频率就在这里声明的

'settings'        : Maintains the run time settings record in eeprom and makes it available
                    to all modules.
                    全局中主要的参数设置，$$命令打印出来的参数都是这里设置的

                    上电读取EEPROM的值，如果读取失败调用default值，都在这里

'eeprom'          : A library from Atmel that provides methods for reading and writing the eeprom with 
                    a small addition from us that read and write binary streams with check sums used 
                    to verify validity of the settings record.
                    存放参数的作用，有关于EPROM的读写函数
'nuts_bolts.h'    : A collection of global variable definitions, useful constants, and macros used everywhere
                      一些全局变量的定义

'serial'          : Low level serial communications and picks off run-time commands real-time for asynchronous 
                    control.
                    串口控制台

'print'           : Functions to print strings of different formats (using serial)

                   打印不同格式的字符串函数在这里定义的

大致框架如下所示